1. Field of the Invention
The present invention relates to landscaping implements and tractor towed implements, and particularly to an automated ripper depth adjustment apparatus which automates the process of adjusting the depth of the ripper on a box scraper, adjusting the depth of all shanks simultaneously.
2. Description of the Related Art
The box scraper is a device commonly used in landscaping for leveling and grading soil. The box scraper may be mounted on the three point hitch of a tractor and used for backfilling and grading during building construction. It may also be used for plowing or breaking soil for agricultural applications. The box scraper usually includes four to six rippers or scarifiers. While the scraper may be raised and lowered as a unit, one of the problems with the conventional box scraper is that ordinarily the depth of the rippers has to be adjusted manually by removing a pin from the shank of the ripper, raising or lowering the height of the ripper, aligning a hole in the shank of the ripper with holes in the frame of the box scraper, reinserting the pin, and locking the pin. Consequently when the tractor operator wishes to adjust the depth of the rippers, he must stop the tractor, get off and move to the rear of the tractor, manually adjust the depth of up to six rippers, and remount the tractor. The process is tedious, physically wearing, and occasionally hazardous.
It is therefore desirable to have an automated apparatus for adjusting the depth of all the rippers simultaneously. U.S. Pat. No. 2,611,305, issued Sep. 23, 1952 to R. D. Acton, teaches a device for controlling the depth of tractor towed implements and generally teaches a complicated device which includes a ground engaging gauge wheel to control the depth operated by a hand crank with an intervening mechanism including a lever attached to a reciprocating plunger in a cylinder guide, attached to a flexible power transmitting element inside a flexible housing, attached to a screw jack mechanism reciprocating in a guide. While the Acton patent teaches a device which will raise or lower the depth of an entire implement, it does not teach a device which will raise or lower the depth of a ripper shank supported within the implement while maintaining the same depth for the frame.
U.S. Pat. No. 3,539,018, issued Nov. 10, 1970 to R. L. Sprenkel, describes a device which includes rippers fixedly attached to a box beam, the box beam being pivotally attached to a bottom link, the bottom link being fixedly attached to a plate. Hydraulic cylinders raise and lower the plate in order to raise and lower the entire apparatus, while another set of hydraulic cylinders raise and lower the box beam to adjust the angle of attack of the rippers. In the Sprenkel device, the depth of the rippers with respect to the box beam is not adjustable.
U.S. Pat. No. 4,679,635, issued Jul. 14, 1987 to E. L. Fields, shows a tilling device with rippers which is raised and lowered by a winch and cable. Each ripper blade is kept biased against a set screw by a hydraulic cylinder and piston in order to maintain a uniform depth of tilling. The depth is adjusted manually by setting a set screw for each ripper.
U.S. Pat. No. 5,366,024, issued Nov. 22, 1994 to D. A. Payne, discloses a device for accurately setting repeatable depths of a tractor towed implement. A hydraulic cylinder controls raising a lowering the implement. As the cylinder extends, a link causes an operating member to contact a poppet valve on a hydraulic valve which controls the cylinder in order to prevent further extension of the cylinder. The operating member has a depth gauge and a hand crank to preset the depth of the implement. The Payne patent does not disclose a device for controlling the depth of ripper blades while maintaining the same frame depth.
Other, less relevant patents showing improvements to box scrapers and tractor hydraulic systems include U.S. Pat. No. 4,046,399, issued Sep. 6, 1977 to Zeuner, et al., U.S. Pat. No. 4,815,542, issued Mar. 28, 1989 to R. J. DePlazes, and U.S. Pat. No. 5,172,499, issued Dec. 22, 1992 to J. Griffin. The Zeuner patent describes an apparatus for permitting hydraulic control of a towed implement from the cab of a tractor without routing hydraulic lines into the cab by installing an electro-hydraulic valve on the towed implement, a hydraulic supply and drain connected between the tractor and the electro-hydraulic valve, and an electric switch in the cab. The DePlazes patent teaches an improvement to a box scraper for fine leveling of the ground surface by placing a U-shaped channel behind the bottom edge of the scraper blade. The Griffin patent shows a combined box scraper-loader in which a pivoting bottom wall of a loader may be detached for use of the implement as a scraper.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. In particular, none of the above inventions and patents are seen to describe an apparatus which raises and lowers ripper blades within the frame of a towed implement simultaneously by use of an automated lever. Thus a automated ripper raiser for tractors solving the aforementioned problems is desired.